Low profile solar tracking systems and methods

ABSTRACT

A solar energy collection system comprises a frame for mounting the system on a suitable substrate and a plurality of solar panels disposed adjacent to one another on the frame. A first set of the solar panels are movable relative to a second set of the solar panels, for tracking movement of the sun during the day. Solar panels of the first set are arranged in alternating fashion with solar panels of the second set. In some embodiments of the invention, the panels in the second set of solar panels are stationary. The second set of solar panels, in some embodiments, are disposed substantially flat, relative to the frame and the substrate on which the frame is mounted. In some embodiments, differing from those in which the second set of solar panels are stationary, the second set of solar panels may be arranged to be movable relative to the first set of solar panels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. 120 of U.S.application Ser. No. 12/953,119, entitled Low Profile Solar TrackingSystems and Methods, and filed on Nov. 23, 2010, now allowed andscheduled to issue as U.S. Pat. No. 9,347,692 on May 24, 2016, which inturn claims the benefit under 35 U.S.C. 119(e) of the filing date ofProvisional U.S. Application Ser. No. 61/272,965, filed on Nov. 24,2009, and expressly incorporated herein by reference, in its entirety.

BACKGROUND OF THE INVENTION

The present invention is in the technical field of collecting solarenergy. More particularly, the present invention is in the technicalfield of systems that provide an infrastructure for the mounting ofsolar energy collection devices to the rooftop of a commercialstructure\dwelling such that the solar energy collection devices areoptimally orientated to the radiation emitted by the sun, as ittraverses the sky, from sunrise to sunset. The tracker assembly may alsobe implemented on patio covers, car ports, parking lot shade structures,and the like.

Prior practice, with respect to the attachment of solar energycollection devices to commercial structures\dwellings, such asphotovoltaic (PV) solar panels, is to arrange the solar panels in anarray, attaching each panel to the structure's rooftop. In this case,the panels may be arranged in an array mounted flat, or flush, to thedwelling's roofline; mounted in rows wherein each row is tilted at afavorable angle to the sun, typically the location's latitude; arrangedin rows wherein each row is, in turn, attached to a single axis trackersystem; or arranged in rows or other groupings, wherein each grouping ofsolar panels is attached to a dual axis tracker system.

Each of these configurations has their advantages and disadvantages. Anadvantage of the stationary flush mount configuration is that it permitsthe greatest number of solar panels to be mounted to the structure,thereby providing the greatest utilization of rooftop area. Adisadvantage of the stationary flush mount configuration is that thepanels are not optimally orientated to the position of the sun, otherthan when the sun is normal or perpendicular to the panel surface,thereby reducing the overall efficiency of the system. Anotherdisadvantage of this configuration is that when the panels areconfigured contiguously in a large array, maintenance of any one panelin the array can be problematic. In most cases, each panel is rigidlyattached to its underlying roof attachment structure and may not beeasily removed. In these cases, maintenance personnel are forced to walkon top of the glass covered solar panels, thereby risking damage to eachpanel traversed.

An advantage of the single and dual axis tracker mount configurations isthat these approaches provide for higher efficiency output per panel,since each panel is more optimally orientated towards the sun during thecourse of the day. A disadvantage of such tracking configurations isthat, due to shading, adjacent rows of panels are typically not mountedcontiguous to one another, but, rather, are separated by an optimaldistance. The separation of adjacent rows results in a poorerutilization of rooftop area and, in turn, reduces the overall efficiencyof the system. Another disadvantage of many single and dual axistrackers is that, because the tracker rotates each panel about itslongitudinal axis, the standoff height of the panels must be high enoughsuch that when rotated to their extreme, the panel does not contact thedwelling. This increased standoff height presents higher bending momentloads onto the roof attachment structure in the presence of wind forcesand is aesthetically undesirable, especially on sloped rooflines whichmay not have a parapet.

SUMMARY OF THE INVENTION

The present invention is a system for providing solar energy collectionwith a modular design or array of solar energy collection devices orpanels angled to the position of the sun. The solar collection systemsdevised in the present invention have either a combination of fixedpanels and tracking panels or only tracking panels, both kinds of panelsconverting sunlight incident upon them to electrical power. The trackingpanels of the present invention follow the daily movement of the sun toefficiently collect solar power from dawn to dusk. The present inventionincludes systems for providing both single axis and dual axis solartracking. The first axis of the system is used to track solar dailychanges, the tracking panels adding power to the system when the sun ismoving through zenith between approximately 10 AM to 2 PM. The shadowingof the tracking panels is minimal to zero at noon. The second axis ofthe system is used to adjust to solar seasonal changes by inclining thesolar panel module or system to the appropriate angle. Both axes aredriven by motors that are controlled by hardware and programmablesoftware that seeks optimum angular positions both daily and seasonally.The system and software is designed to account for in site installationat any latitude to efficiently track the daily and/or seasonalpositions. The present systems in general are also designed to besufficiently rugged to withstand forces of the elements such as wind,rain, etc., and to meet international and national building codespecifications. In addition, the physical structure of the system isdesigned for ease of installation and maintenance because of its modulardesign. Such modular design of the solar panels of the present inventionallows connections to adjacent modules or arrays on a variety of sitessuch as residential roof tops, factory rooftops, large groundinstallations, on patio covers, car ports, parking lot shade structuresetc.

One embodiment of the invention is comprised of a central structuralchannel frame upon which solar panels are mounted, with theirlongitudinal axis perpendicular to the longitudinal axis of thestructural channel frame. Each pair of solar panels shares a commonhinge mechanism and each panel of the pair is attached to the hinge onits edge, which is parallel to the longitudinal axis of the panel unit.The hinge, in turn, is mounted to the central structural frame.Attachment to the edge of each solar panel is advantageous because itpermits a smaller standoff height to be used in comparison to thestandoff height that must be used when rotating the solar panel aboutits longitudinal centerline axis.

A linear actuator moves a force transmission drive shaft back and forthwithin the central structural frame. The drive shaft contacts a camsurface on the underside of each panel, the force of which results inthe panel rotating about its hinge axis. In one embodiment, every otherpanel shares the same rotary position. In other words, in the morning,the 1^(st) and 3^(rd) panel will rotate together from an eastwardlyfacing direction to horizontal, the 2^(nd) and 4^(th) panels will remainhorizontal. In the afternoon, the 1^(st) and 3^(rd) panels will remainhorizontal, while the 2^(nd) and 4^(th) panels will rotate fromhorizontal to a westerly facing direction. In a variation of thisembodiment where there are alternating fixed and tracking panels, the1^(st) and 3^(rd) panel will rotate together from an eastwardly facingdirection in the morning all the way to a westerly facing direction atthe end of the day, with the 2^(nd) and 4^(th) panels being fixed, andtherefore horizontal. Each of these systems, of course, may be equippedwith either a single axis for daily tracking only or a dual axis fordaily tracking as well as seasonal tracking.

In order to minimize the effects of shading on adjacent panels of a pairof panels that share the same hinge axis by a neighboring panel of anadjacent panel pair, reflector surfaces are mounted to reflect photonson to the area of the shaded panel. In addition, back-tilting of theshaded panel may also be used to minimize the length of the shadow castupon it. The common hinge mechanism also permits each panel to berotated up and out of the way for easy maintenance access after beingdisengaged from its attached cam surface via a quick-disconnectmechanism. As will be seen hereinafter, the present invention isbelieved to be an improvement over prior practice in the followingareas:

1) Maximum Energy Production: In installations where the structure'sroof size is the limiting constraint, the present invention, in itssingle axis embodiment, does not require space between adjacent rows ofpanels. This permits the highest utilization of rooftop area to beachieved. Although each panel's individual efficiency is less than thatachievable with a prior practice single axis tracker, the combined poweroutput will be greater due to the higher number of panels installed. Inaddition, the system's integrated cleaning system ensures that the solarpanels and reflectors are clean of dirt and other deposits that reducethe system's power generation efficiency.

2) Low Profile Design: The present invention's panel positioning drivesystem results in a system that is visually indistinguishable from atypical low profile stationary flush mount installation. In addition,the inventive system's low profile design is aesthetically pleasing, andwill minimize bending moment loads on to the roof attachment structurein the presence of wind forces. This invention can also be easilyattached to sloped roof lines.

3) Easy Maintenance: The innovative design of the inventive systemfacilitates maintenance by providing a quick-disconnect release systemwhich, when activated, permits the solar panel to be rotated up and outthe way. This configuration permits easy access to the underlyingtracker mechanism and roof structure.

More particularly, there is provided a solar energy collection system inaccordance with the principles of the invention, which comprises a framefor mounting the system on a suitable substrate and a plurality of solarpanels disposed adjacent to one another on the frame. A first set of thesolar panels are movable relative to a second set of the solar panels,for tracking movement of the sun during the day. Advantageously, solarpanels of the first set are arranged in alternating fashion with solarpanels of the second set. In some embodiments of the invention, thepanels in the second set of solar panels are stationary. The second setof solar panels, in some embodiments, are disposed substantially flat,relative to the frame and the substrate on which the frame is mounted.In some embodiments, differing from those in which the second set ofsolar panels are stationary, the second set of solar panels may bearranged to be movable relative to the first set of solar panels.

In preferred embodiments, a first solar panel in the first set ispivotally connected to a second solar panel in the second set, to form atracking unit. The solar energy system as a whole preferably comprises aplurality of tracking units. A hinge connects the first and second solarpanels in each of the tracking units. A hinge daily axis lies along thehinge, wherein each of the first and second panels in each of thetracking units pivots about the hinge daily axis independently of theother of the first and second panels. The frame preferably comprises astructural channel frame having a channel portion, and a drive systemfor pivoting each of the first and second panels in a tracking unit isdisposed within the channel portion.

The drive system preferably comprises a drive shaft extending lengthwisethrough the channel portion, and a plurality of camming systems attachedto the drive shaft for pivoting each one of the first and second solarpanels in each tracking unit independently of the other one of thattracking unit's first and second solar panels.

Preferably, a plurality of tracking units are disposed on the structuralchannel frame. The system preferably comprises a plurality of structuralchannel frames, each of which accommodates the aforementioned pluralityof tracking units. Each of the solar panels has a top surface and abottom surface. Preferably, the system incorporates features whichmitigate the shading of portions of one solar panel by adjacent panelswhich have been pivoted to better track the sun's position. Thesefeatures preferably include a reflector disposed on at least one of thesolar panels of a tracker unit to improve solar collection efficiency ofthe system. In presently preferred embodiments, the reflector comprisesa first reflector disposed on the bottom surface of one of the first andsecond solar panels, for redirecting light to a shaded portion of thetop surface of the other one of the first and second solar panels. Asecond reflector may be disposed on the top surface of the other of thefirst and second solar panels, for redirecting light to the firstreflector.

Still another advantageous feature of the present invention is that thesystem comprises a liquid supply line and liquid jet orifices forcleaning the solar panels. The cleaning may be scheduled to occurautomatically, or may be performed manually, upon demand, by theactuation of an appropriate switch on the control unit. Yet anotherunique and advantageous feature is that the system further comprises aquick-disconnect release mechanism for disengaging a panel from thedrive system so that it can be manually moved for maintenance purposes.

In yet another aspect of the invention, there is provided a solar energycollection system, which comprises a frame for mounting the system on asuitable substrate. The system comprises a pair of solar panels disposedadjacent to one another and independently movable relative to oneanother, wherein each of the solar panels has a top surface and a bottomsurface. A reflector is disposed on the bottom surface of one of thepair of solar panels, for redirecting light to a shaded portion of thetop surface of the other one of the pair of solar panels. Preferably,the solar panels further include a second reflector disposed on the topsurface of the other of the first and second solar panels, forredirecting light to the bottom surface reflector.

In still another aspect of the invention, there are disclosed unique andadvantageous methods for collecting solar energy, using a systemcomprising a frame and an array comprising a plurality of solar panelsconnected to the frame, wherein the frame is mounted onto a suitablesubstrate, such as a rooftop. The methods comprise steps of programminga controller in the system to track the sun's position as the dayprogresses, accounting for seasonal variation, as well as using thecontroller to move some of the solar panels in the array relative toother stationary solar panels in the array. Accordingly, the movingsolar panels pivot in order to maintain an orientation facing the sun asthe relative position of the sun to the solar panel array changes.

The invention, together with additional features and advantages thereof,may best be understood by reference to the following description takenin conjunction with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one version of the tracking assembly ofthe present invention, showing solar panels mounted to two trackerunits;

FIG. 2 is a plan view of the structural frame that attaches to theunderside of each solar panel;

FIG. 3 is a side view of the tracking assembly, showing a singletracking unit;

FIG. 4 is an end view of the tracking assembly;

FIG. 5A is a side view of the tracking assembly, showing a singletracking unit in the horizontal tracking start position;

FIG. 5B is a side view of the tracking assembly, showing a singletracking unit in a typical morning tracking position;

FIG. 5C is a side view of the tracking assembly, showing a singletracking unit in the horizontal tracking noon position;

FIG. 5D is a side view of the tracking assembly, showing a singletracking unit in a typical afternoon tracking position;

FIG. 6 is a side view of the tracking assembly, comprised of twotracking units, showing the reflectance of photons on to the shadedportion of a solar panel;

FIGS. 7A and 7B are side views of the tracking assembly, comprised oftwo tracking units, with the solar panels rotated into the maintenanceposition;

FIG. 8A is a side view of the tracking unit, showing details of cleaningand reflector design;

FIG. 8B is a side view of two tracking units, showing trajectory pathsof pressurized cleaning fluid onto solar panel and reflectors;

FIG. 9A is a perspective view, showing rows of single axis trackingassemblies mounted in a flush mount configuration;

FIG. 9B is a front perspective view, showing rows of single axistracking assemblies mounted in a flush mount configuration, with solarpanels tilted towards the sun in a typical tracking position;

FIG. 9C is a rear perspective view, showing rows of single axis trackingassemblies mounted in a flush mount configuration, with solar panelstilted towards the sun in a typical tracking position;

FIG. 9D is a perspective view, showing rows of single axis trackingassemblies mounted in a fixed tilt mount configuration, with spacebetween adjacent rows;

FIG. 9E is a perspective view, showing rows of dual axis trackingassemblies, mounted with space between adjacent rows; and

FIG. 10 is a top view of a different embodiment of a dual axis systemwith an assembly of alternating fixed and tracking solar panels.

DETAILED DESCRIPTION OF THE INVENTION

Referring now more particularly to the drawings, FIG. 1 shows aperspective view of a tracking assembly 200, which is comprised of oneor more tracking units 100. In this particular figure, only two trackingunits are shown for clarity. In this embodiment, each tracking unit 100has two solar panels 10 and provides a hinge shaft 12 shared between twosubstantially identical and adjacent solar panels 10. In a trackingassembly 200, the tracking units 100 share a common structural channelframe 14.

FIG. 2 shows a plan view of the method of attachment of solar panels 10to the tracking unit. The underside of each solar panel 10 rests on arespective panel frame 16 and is secured using panel clips 18. Each endof each panel frame 16 is connected to a hinge collar 20, which rotatesabout the fixed hinge shaft 12. The centerline of the hinge shaft 12defines the hinge daily axis 22, and is the axis of rotation for thesolar panel 10. Frame mounting bracket 24 is used to secure the hingeshaft 12 to the underlying structural channel frame 14, and also may beused to attach the tracking assembly 200 to the underlying substrate,typically a roof. FIG. 2 also defines section A-A, which is rendered inFIG. 3.

FIG. 3 shows linear actuator 26 connected to drive shaft 28 usingactuator coupler 30. The drive shaft is supported by the drive shaftroller 32, housed in drive shaft roller carrier 34, which is attached tothe structural channel frame 14. Cam bearing block 36 is attached to thedriveshaft 28. As the drive shaft translates, the cam bearing block'scam bearing 38 travels in the slot of a cam 40. As the cam bearing 38encounters the inclined slot of the cam 40, the force of contactgenerates a torque about the hinge daily axis 22 and causes the cam 40and attached solar panel 10 to rotate upward, about hinge shaft 12, frompanel stop 42. Cam 40 is attached to the hinge shaft 12 via cam hingecollar 44, as shown in FIG. 2. The linear actuator 26 is powered by anAC or DC motor that is of low power and is controlled by a system thatis seasonally programmed to accurately track the daily solar motion. Adrive shaft coupler 46 is used to connect two drive shafts together,thereby permitting a single linear actuator 26 to control one or moretracking assemblies. An optional seasonal axis 48 is also installed atthe base of the tracking module that is controlled and powered by a lowpower AC/DC motor. FIG. 9E shows the location and structure of oneoptional seasonal axis 48.

FIG. 4 shows an end view of a tracking assembly 200, with the solarpanels 10 in a horizontal position. In the center of the structuralchannel frame 14 is the drive shaft 28. On each side of the drive shaftresides the cam 40. The cam 40 on the left of the driveshaft is used torotate the panel located in the back of the hinge shaft 12, while thecam 40 located on the right side of the drive shaft is used to rotatethe panel mounted in front of the hinge shaft 12. Each cam 40 has amating cam bearing block 36, mounted to drive shaft 28, which containscam bearing 38, a guide bearing 50, and a bearing shaft 52 (Note: cambearing block 36, cam bearing 38, guide bearing 50, and bearing shaft 52are shown for the left side cam 40 only, and have been omitted on theright side cam 40 for clarity). As the drive shaft 28 moves, guidebearing 50 contacts structural frame 14 and is used to provide stabilityof the driveshaft 28. The end of each cam 40 is connected to a cam hingecollar 44, which is mounted concentrically to the fixed hinge shaft 12.On each side of the drive shaft resides a wire trough 54, which providesfor the routing and protection of solar panel and control system wiring.

FIG. 5A-5D show the progression of solar panel position from sunrise tosunset. FIG. 5A shows both panels belonging to the same tracking unit inthe horizontal flat position. As the sun rises, FIG. 5B shows one of thepanels of an adjacent pair of panels facing the sun, and rotated aboutthe hinge daily axis 22, so that the panel's normal is optimally alignedto the sun's radiation. At noon, as shown in FIG. 5C, when the sun is atits zenith, this panel is rotated back so that both panels arepositioned horizontally, relative to the substrate on which they aremounted, such as a roof, to receive the perpendicular solar radiation.As the sun sets, FIG. 5D shows the other panel of the adjacent pair ofpanels facing the sun, and rotated about the hinge daily axis 22, sothat the panel's normal is optimally aligned to the sun's radiation.With multiple tracking units in the same assembly, every other panel(alternating panels) will share the same rotary position as shown inFIG. 6. Thus, for an assembly of two tracking units, in the morning the1^(st) and 3^(rd) panels will rotate together from an eastwardly facingdirection to horizontal, the 2^(nd) and 4^(th) panels will remainhorizontal. In the afternoon, the 1^(st) and 3^(rd) panels will remainhorizontal, while the 2^(nd) and 4^(th) panels will rotate fromhorizontal to a westerly facing direction.

Although the present invention does not preclude the mounting of thetracking units at non-optimal centerline distances, such as may be donewhen high area utilization is not an important design consideration,optimal area utilization is achieved when mounting the tracking units soas to minimize any spacing or gap between solar panel pairs. Of course,doing so results in the shading of portions of intermediate panels. FIG.6 presents a side view of a tracking assembly, comprised of two trackingunits, showing an innovative feature of the invention which permits thereflectance of incident photons 55 onto the shaded portion of a solarpanel. Shading naturally occurs as the panel is rotated upward to facethe sun and a shadow is cast upon the panel behind it. The presentinvention compensates for the shading by appropriately affixingreflective surfaces on the panels to cast solar radiation onto theshadowed panel surfaces. The configuration of the reflective surface canbe flat, convex, etc., to produce the desired effect. As shown in FIG.6, photons incident upon the inclined panel, strike a hinge reflector56, and are reflected upward to the backside of the adjacent inclinedpanel. A panel reflector 58 is provided on the backside of this adjacentinclined panel to reflect the photons back down onto the flat solarpanel 10 and serve to illuminate that portion of the solar panel 10which is shadowed, and to substantially increase the solar panel's poweroutput. In addition to compensating with reflective surfaces, the shadedflat panel can be (optionally) rotated upward slightly, approximately5-10 degrees, to reduce the length of the shadow cast upon it. Althoughthe slot in cam 40 is shown as a linear slot, it should be clear to oneordinarily skilled in the art that the geometry of the slot could alsoinclude alternate profiles in order to achieve small upward rotations ofthe shaded panel away from the sun, as the cam bearing 38 reaches theend of the slot in cam 40.

As the panels track the sun, the amount of shading will proceedprogressively as a function of panel tilt angle. In the case where twotracking unit panels abut one another, and the shaded panel lies flat,this relationship may be approximated by the equation: S=(1/cosQ−1)*100, where S is the percent of the panel shaded and Q is the paneltilt angle with respect to the horizontal (see FIG. 6). For example, thefraction shaded at 45 degrees is approximately 41%. At angles less than45 degrees, the percentage of shading will progressively decrease. Forexample, at 30 degrees the shading percentage is approximately 15%. Inother embodiments, where there might be a gap between the panels, or theshaded panel has been rotated slightly upwardly, the shading factors andrelationship will vary, but the general principles addressed by theinvention will remain.

FIGS. 7A and 7B show a side view of a tracking assembly, comprised oftwo tracking units 100, with their respective solar panels rotated intoa maintenance position. To activate this functionality, a panel releasehandle 60 (FIGS. 5A and 5B) is retracted. Retracting this handledisengages attachment of panel frame 16 from cam 40. The solar panel canthen be manually rotated about its hinge daily axis 22 into an uprightposition. This position then permits the solar panel to be easilyremoved for repair or replacement, to gain access to the underlyingtracking unit, or to gain access to another panel that may be located inan adjacent tracking assembly row. To re-engage the solar panel, it islowered back into the horizontal position, with the panel release handle60 in the retracted position. Upon release of the handle, the releasehandle return spring 62 (FIG. 2) engages the release handle and securesthe panel frame 16 to the cam 40.

FIGS. 8A and 8B show details of an automated cleaning apparatus, whichis used to clean the solar panels and reflectors of dirt and otherdeposits that reduce the solar panels' power generation efficiency.Under computer control, the cleaning process is programmed to occur atregular intervals, or manually, if desired, such that solar panelefficiency is optimally maintained. FIG. 8A is a side view of thetracking unit 100, showing details of the cleaning and hinge reflectordesign. In this design, under computer control, an external valve (notshown) is opened, permitting pressurized cleaning fluid to enter thehollow hinge shaft 12 by means of a water supply line with grommet 64.The pressurized cleaning fluid then exits the hinge shaft 12 throughnumerous water jet orifices 66, and is distributed evenly along theentire length of hinge shaft 12. FIG. 8B shows the pressurized cleaningfluid exiting the water jet orifices 66 in a trajectory that strikes theinclined panel 10 and hinge reflector 56. In addition, pressurizedcleaning fluid also exits the water jet orifices 66 in a trajectory thatstrikes the backside of the next inclined panel, such that the panelreflector 58 is also cleaned.

FIGS. 9A-9E show the present invention in a variety of systemconfigurations, using the tracking assembly 200. Since the trackingassembly 200 is modular, the mounting on most sites will be rapid. Thesite can be previously affixed with mounting posts, and laid out in anaccurate geometrical array, consistent with the dimensions of thetracking assembly.

FIG. 9A shows a perspective view of a flush mount configuration trackingsystem 300A. In this configuration, the system is comprised of rows oftracking assemblies 200 mounted adjacent to one another. An advantage ofthis configuration is that the solar panel arrangement uses all allottedspace for solar power collection, thus producing a greater power outputper allotted area. FIGS. 9B and 9C show a front and rear perspective,respectively, of this configuration with the solar panels tilted towardsthe sun in a typical tracking position.

FIG. 9D is a perspective view of a fixed tilt mount configurationtracking system 300B. In this configuration, the system is comprised ofrows of tracking assemblies 200, each mounted at an optimum fixed tiltangle towards the sun, with space between adjacent rows. Each trackingassembly 200 is mounted at a fixed tilt angle, using a fixed tiltmounting pedestal 68.

FIG. 9E is a perspective view of a dual axis tracking system 300C. Inthis configuration, the system is comprised of rows of trackingassemblies 200, with space between adjacent rows. Each tracking assembly200 is mounted to a seasonal axis 48 to provide the 2^(nd) trackingaxis.

FIG. 10 is a perspective view of a dual axis tracking system comprisingfixed solar panels (10A) as well as tracking solar panels (10B). The2^(nd) and 4^(th) panel will rotate together from an eastwardly facingdirection in the morning all the way to a westerly facing direction atthe end of the day, with the 1^(st) and 3^(rd) panels being fixed, andtherefore horizontal. This system is equipped with dual axes, one fordaily tracking only and one for seasonal tracking. Because of thestaggered design, air flow surrounds each panel assuring all panels aresufficiently cooled.

Accordingly, although exemplary embodiments of the invention have beenshown and described, it is to be understood that all the terms usedherein are descriptive rather than limiting, and that many changes,modifications, and substitutions may be made by one having ordinaryskill in the art without departing from the spirit and scope of theinvention, which is to be limited only in accordance with the followingclaims.

What is claimed is:
 1. A solar energy collection system, comprising: a frame comprising a plurality of tracking units for mounting the system on a suitable substrate, said frame lying along an axis, a plurality of said plurality of tracking units being disposed linearly along a portion of said frame to form a tracking assembly; and a plurality of solar panels disposed adjacent to one another on said frame, each of said solar panels comprising a top surface for collecting solar energy and directly converting the solar energy into electricity; a first set of said solar panels being movable about daily axes relative to a second set of said solar panels, the second set of said solar panels also being movable about daily axes relative to the first set of said solar panels, for tracking movement of the sun during the day, the daily axes lying in orientations which are generally orthogonal to an orientation of the frame axis, solar panels of said first set being arranged in alternating fashion with solar panels of said second set, each of said tracking units comprising a solar panel from each of said first and second sets; the plurality of said plurality of tracking units being arranged end-to-end on each tracking assembly, wherein the daily axes of each tracking unit are not coincident with one another on that tracking assembly; each of the first and second panels in each said tracking unit pivoting about its daily axis independently of the other of said first and second panels in that same tracking unit; and a drive system for pivoting each of said first and second panels in a tracking unit, said drive system being disposed on said frame; wherein a first solar panel in said first set is pivotally connected to a second solar panel in said second set, about one of said daily axes, on a hinge disposed therealong, to form one of said tracking units, the hinge being at a lowest position relative to each of the first and second solar panels, as measured from the frame, such that neither of the first and second solar panels is pivotable to an orientation where any part of the first or second solar panel is located at a position lower than the position of the hinge.
 2. The solar energy collection system as recited in claim 1, wherein the panels in said second set of solar panels are disposed in a plane substantially horizontally, said plane being substantially parallel to planes in which said frame and the substrate on which the frame is mounted are disposed, the top surfaces of the second set of solar panels facing upwardly when lying in said substantially horizontal orientation.
 3. The solar energy collection system as recited in claim 1, wherein the portion of the frame along which a plurality of said plurality of tracking units are disposed linearly comprises a structural channel.
 4. The solar energy collection system as recited in claim 3, wherein said drive system comprises a drive shaft extending lengthwise through said channel, and a plurality of camming systems attached to said drive shaft for pivoting each one of the first and second solar panels in each tracking unit independently of the other one of that tracking unit's first and second solar panels.
 5. The solar energy collection system as recited in claim 3, and further comprising a plurality of said structural channels, each of which accommodates a plurality of said plurality of tracking units.
 6. A method for collecting solar energy, using a system comprising a frame and an array comprising a plurality of solar panels connected to the frame, the plurality of solar panels comprising a first set of first and second solar panels and a second set of first and second solar panels, wherein the first and second solar panels in each of the first and second sets are joined to one another by a hinge so that the first and second solar panels in each of the first and second sets are movable relative to one another, and further wherein the frame is mounted onto a suitable substrate, the method comprising steps of: calculating a panel tilt angle which maximizes solar energy collection of the system for the position of the sun in the sky at a particular time of day by factoring into consideration an orientation of a first panel relative to the sun to maximize an incidence of sunlight on a top surface of the panel; using a controller to move the first solar panel in each of the first and second sets in the array about a daily axis lying along the hinge, relative to the second solar panel joined thereto by the hinge, to the calculated panel tilt angle to thereby track the sun's position as a day progresses, during a first portion of the day; and using the controller to move the second solar panel in each of the first and second sets in the array about the daily axis, relative to the first solar panel joined thereto by the hinge, during a second portion of the day.
 7. The method as recited in claim 6, wherein the first portion of a day comprises a period ending when the sun reaches its zenith, and the second portion of the day comprises a period beginning when the sun reaches its zenith.
 8. The method as recited in claim 6, and further comprising a step of using the controller in said system to move at least portions of the array about a seasonal axis to account for seasonal variations in the position of the sun in the sky.
 9. The method as recited in claim 6, and further comprising a step of using the top surfaces of each of the plurality of solar panels to directly convert sunlight into electricity.
 10. The method as recited in claim 6, wherein the plurality of solar panels comprises additional sets of first and second solar panels wherein each additional set of first and second solar panels comprises a hinge lying along a daily axis which joins the first and second solar panels together, and further wherein the steps of using the controller to move the first solar panel and using the controller to move the second solar panel also move the first and second solar panels of the additional sets of first and second solar panels.
 11. The method as recited in claim 10, wherein during the step of using the controller to move the first solar panels of each set, the first solar panels are moved simultaneously.
 12. The method as recited in claim 10, wherein during the step of using the controller to move the second solar panels of each set, the second solar panels are moved simultaneously.
 13. The method as recited in claim 6, and further comprising a step of reflecting incident light from the second set of solar panels onto the top surface of one of the first and second solar panels in the first set of solar panels, to compensate for shading effects.
 14. The method as recited in claim 6, and further comprising: disengaging the first and second solar panels in the first set of solar panels from a drive system which the controller actuates to rotate the first and second solar panels about the hinge in the first set; and rotating at least one of the first and second solar panels manually about the hinge to an upright position, to perform maintenance on the first set of solar panels, the drive system, or the solar panels themselves.
 15. The method as recited in claim 6, and further comprising: opening a valve to permit cleaning fluid to flow through a supply line; permitting the cleaning fluid to flow through a hollow shaft of the hinge of the first set of solar panels; and ejecting the cleaning fluid from the hollow shaft onto the first and second solar panels of the first set of solar panels. 